The present invention is in the field of dental floss holders and more particularly those having leverage means of stressing the floss with tension for the purpose of increasing the utility of the floss and improving user control of the floss while the floss is used to clean spaces between the teeth and periodontal regions, aiding greatly in the reduction of tooth decay, gum diseases and gingivitis.
Prior art teaches methods of manufacturing flossing tools which make use of fulcrum means between the portion which is held by the user, being a "U"-shaped handle, and the portion which holds the floss, being a bifurcated extension. One such design is taught by Johnson, U.S. Pat. No. 4,192,330, filed Mar. 11, 1980. In the same filing, a way to use a loop of floss as a removable insert is described, for the purpose of refilling the floss holder with fresh floss when the floss is frayed or used up. The floss loops around the floss holder portion of the tool and is held in place by "grooves of arms 122 and 124 and under terminal retention lips 138 at the junction 140". When the handle of the holder is collapsed the bifurcated extension spreads, and a tension is placed upon the floss, causing the floss to be stretched taut. Said tensioning of the floss is beneficial in the use of flossing tools, as taught in a number of patents in addition to Johnson. Among the others: N. S. Brody, U.S. Pat. Nos. 2,811,162, filed Oct. 29, 1957; Yafai, 4,304,246, filed Dec. 8, 1981; Schiff, D251,074, filed Feb. 13, 1979; Badoux, 4,736,757, Apr. 12, 1988.
In the Yafai patent, a loop of floss is used, as in the Johnson patent, and held in its place by a spur 30 and trough-like configuration at the base of the frame 11a of the Dental Floss Holder.
A number of the other devices use a short strand of floss which is not a loop, but held at each end by affixing the ends of the strand to prongs, as in Badoux, or by molding the plastic of the holder about the ends of the strand of floss, as illustrated in the design patent by Schiff. However, the slippery nature of dental floss, made up of many finer strands, often permits it to slide from its intended mounting, and more important, the force required to effect flossing and to urge the floss through very tight teeth is such that even the methods which employ loops are not sufficiently reliable to hold the floss in place upon the flossing tool when the force required to work on subject teeth is applied. Ten pounds or more pressure upon a flossing tool can be necessary to insert or remove a strand of floss from between very tight teeth and in use the flosser is pushed and pulled in several directions causing great forces to be effected upon the floss from many angles.
Working example of existing designs show that the holding in place of the strand of floss upon the flossing tool is a major problem which must be overcome in order to increase efficiency and aid in the convenient use of flossers.
When in use such great force in urging the floss between the teeth has the tendency to distort the shape of the flossing tool, especially if the tool is made of plastic or other flexible material, which then allows the floss to pull loose or to derail from its mounting, thus effectively limiting the utility of prior flossers in the purposes for which they were designed.